When measuring the enthalpy of combustion/enthalpy of reaction for a combustion reaction, the results from practical investigations are usually quite different to
theoretical values. Identify the reasons that this may be most likely below.

A. Insulation on the coffee cup calorimeter is poor, and heat isreleased to the environment. The measured temperature is less
than the theoretical values.

B. Insulation on the can calorimeter is poor, and heat is absorbedfrom the environment. The measured temperature is higher than
the theoretical values.

C. The heat from the combustion is distributed evenly throughout
the can calorimeter, meaning that it is more accurate than the best theoretical predictions.
D. Heat is lost to the environment between the source of combustion and the calorimeter. The measured temperature is less than the theoretical values.

The following reaction shows the products when sulfuric acid and aluminum hydroxide react. al(oh)3 + h2so4 → al2(so4)3 + h2o the table shows the calculated amounts of reactants and products when the reaction was conducted in a laboratory. initial mass and yield sulfuric acid aluminum hydroxide initial amount of reactant 40 g 15 g theoretical yield of water from reactant 14.69 g 10.38 g what is the approximate amount of the leftover reactant? 11.73 g of sulfuric acid 10.33 g of sulfuric acid 11.12 g of aluminum hydroxide 13.67 g of aluminum hydroxide

7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.

What was bohr’s contribution to the planetary model